Register Account

Login Help


The K7RA Solar Update


Average daily solar flux and sunspot numbers were down for the second week in a row. Average daily sunspot numbers for January 29 to February 4 were 139, then down to 81.6 the next seven days, and now 54.6 during the February 12-18 (latest) reporting period. The three averages for daily solar flux over the same periods were 151.1, 144.1 and 121.4.

The latest prediction for solar flux is 120 on February 20-21, 125 on February 22-24, 130 on February 25-28, 125 on March 1-5, 120 on March 6, 115 on March 7-14, 125 on March 15 and 130 on March 16-18. Solar flux then rises to 135 on March 23-25.

Predicted planetary A index is 5 on February 20-21, 12 on February 22-23, then 10, 8, 5 and 10 on February 24-27, 18 on February 28 through March 1, 15 on March 2, 10 on March 3-4, then 5 and 7 on March 5-6, 10 on March 7-8, and 5 on March 9-13.

Here is a new Czech Republic geomagnetic forecast, this time from Petr Kolman, OK1MGW.

The geomagnetic field will be mostly quiet February 20-21, quiet to active February 22-23, quiet to unsettled February 24-27, active to disturbed February 28, disturbed on March 1, active to disturbed March 2, quiet to unsettled March 3-4, mostly quiet March 5, quiet on March 6, mostly quiet March 7, quiet to active March 8, quiet to unsettled March 9, quiet to active March 10, quiet March 11-13, mostly quiet March 14, quiet to unsettled March 15, quiet to active March 16-17, and mostly quiet March 18.

Petr believes there is a reduced probability of increased activity on February 22-23.

I received a nice report summary from Jeff, N8II of West Virginia: “It's been a while since I reported in, not too much exciting was happening over December and January. The ARRL 10 Meter Contest conditions were pretty good with a few Russians logged along with a multitude of central and western Europeans. Conditions to Japan were open Saturday evening, but signals were not as strong as the CQWW in October/November. All during December and 45 days after the solstice despite fairly high solar flux numbers and resultant very short skip on 20 meters, the polar and near polar paths were pretty much shut down on 12 meters and 10 meters, and poor most of the time on 15 meters. In the past couple of weeks the increasing polar daylight and decreasing disturbances have really livened up the bands, despite decreased SFI (solar flux) to around 120 recently.

“Going back a week to February 12, I logged UN7AB on 10 meter CW an honest S9 at 1318 UTC. Also worked on 10 CW were several Russians in the southern sixth call area and Ukraine along with TA2AL. Of note also, 10 meters is now open much later to Europe than in December and 20 is still open to southern and western Europe at 2100-2200 UTC most days. The next morning, Friday, February 13, was also noteworthy, logging EY8MM 539 on 12 meter CW at 1247 UTC and UA4PT 579 on 10 meter CW at 1404 UTC. JH1MDJ was S9 on 10 phone at 2300 UTC.

“I worked the Dutch PACC Contest (see on February 14-15. 10 meters was a bit slow to open to Holland, but eventually the little guns were strong enough to work by 1415 UTC and the big guns were loud. Dutch signals on 15 meters were loud all morning. Evening low band conditions were mediocre, but the big guns were fairly loud on 40 peaking 1-2 hours after sunset.

“I made a dozen Dutch QSOs on 80, 30 and 40 meters, but could have done a lot better if I had worked through the European sunrise. I tired of tracking down the very limited number of Dutch stations and checked 15 meter phone at 0100 UTC Sunday to find it wide open to the Far East, finding XW3DT about S5 and both BV0RW and BW2/JP1RIW in Taiwan with S9 signals. A CQ brought a steady run of seven loud JA stations, most of which were S9 before quitting at 0132 UTC. Of note on February 15 was the very late 10 meter opening to S57AL at 1846 UTC and M0BZH at 1931 UTC.

“On February 16 on 15 meter CW a very loud RU0LAX was logged, and then VK6HM (S2) and RA0LMK answered my CQs followed by finding BG9XD about S7. That morning two UA3 area stations answered CQs on 10 CW starting 1438 UTC (rather late), and R5WW and UV1IW were also logged.

“On February 19 RW0CR was S9+ 30-35 db on 15 phone at 0042 UTC and, due to a bout of insomnia, I caught a good 160 meter CW opening from 0448 UTC finding US5, HA8, and F5IN. Then from 0502-0521 UTC running a steady stream (many S9), logging in order OK1, KP2M, DF9, SP9, SP2, US2, S58N, 9A5X, OM7, US0, 9A2, M0, and DK3. Also heard well was TI9/3Z9DX, but no QSO. 160 has been largely completely closed to EU in the early to mid-evening here, so this opening was a surprise probably helped by a low K index and SFI hovering around 120 rather than the 140s and higher in January.

“Today, February 19, was the coldest day of the season with a high of 14 degrees F and wind chill factor never above zero all day.”

Thanks, Jeff!


On February 17, the NOAA Space Weather Prediction Center emailed a notice about a planned temporary shutdown this Saturday which we reported in the ARRL Letter, but as of Thursday February 19 it has been postponed.

Don’t miss the ARRL CW DX Contest this weekend. The Phone portion is the first full weekend in March. The CW weekend begins tonight in North America (0000 UTC Saturday, or 4:00 PM PST/7:00 PM EST) and ends 48 hours later.  For details see

K9LA has a new post on his website, a review of one-way propagation, at .

Here he gives a history of his propagation columns for WorldRadio, then CQ Plus, which ended recently:

Poke around his website. You will find many interesting and informative articles.

For more information concerning radio propagation, see the ARRL Technical Information Service at For an explanation of the numbers used in this bulletin, see An archive of past propagation bulletins is at More good information and tutorials on propagation are at Monthly propagation charts between four USA regions and twelve overseas locations are at

Instructions for starting or ending email distribution of ARRL bulletins are at


Sunspot numbers for February 12 through 18 were 50, 59, 49, 45, 44, 40, and 95, with a mean of 54.6. 10.7 cm flux was 127.6, 124.9, 120.4, 119.6, 118.1, 118.5, and 121, with a mean of 121.4. Estimated planetary A indices were 5, 3, 3, 6, 5, 22, and 19, with a mean of 9. Estimated mid-latitude A indices were 3, 2, 2, 5, 4, 18, and 15, with a mean of 7.




Instragram     Facebook     Twitter     YouTube     LinkedIn